Housing...Inside and Out

October 23, 1998
Ten Hints That Can Help Reduce Moisture in The Home

Buying or building a home is the largest investment most consumers ever make. Too often though the dream home that was expected to last at least 25 to 30 years crumbles into a nightmare of decay sometimes within five years. Moisture is the culprit.

There are several steps that can be taken to help eliminate the moisture problem.

  1. Roof overhangs must be sufficient to ward off falling rain against the base of the home. The overhangs must be positioned so that water runs away from the house not toward the house. 
  2. The crawl space should have a clean smooth surface that is crowned. The distance from the crawl space soil to the bottom of the floor joists should be 18". 
  3. The finished grade around the house should be at or below crawl space grade. It will then direct water from the foundation wall. 
  4. Shrubs and other landscaping should not be planted too close to the house since it might block ventilation. 
  5. Properly placed footing drains are important if water falls at the foundation of the house. 
  6. Make sure siding does not come too close to the finished grade. 
  7. For homes built on a crawl space or conventional foundation, the vents in the crawl space area should be left open year round to enable adequate ventilation. 
  8. The installation of 6 mil polyethylene on the ground in the crawl space will help control the amount of moisture under the home in the crawl space area. Lapping the polyethylene 6" at the seams will decrease seepage of moisture in the area. 
  9. A damproofing layer at the base of the foundation will help keep moisture out of the home. 
  10. Eliminate plumbing leaks under the house that may produce more moisture to the area. If moisture actually collects in pools under the house, then the installation of a sump pump to expel the excess water from the area may be necessary.

These recommendations are not the only things that one can undertake to eliminate moisture damaging situations but they are a beginning point to address the issues. For more information on this subject, please contact your local county extension office and ask for the publications available on moisture and mildew.


Written by Dr. Francis Graham (Retired)

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